Great list that sparked my memory. The tmux scroll back issue was very frustrating for me, and ultimately what made me stop using it. What got me hooked on trying to use it - I do remember being amazed I could close my laptop, go home, and just reopen my laptop and immediately start typing away on my remote terminal without issue most of the time.
A few other issues I do remember running into (probably 10 years ago?):
1. Because it was udp, sometimes a captive portal, work, or hotel firewall blocked it.
2. It was also not installed by default anywhere, so sometimes sysadmins at work were unwilling to install it for me.
3. I sometimes ran into issues with color handling and utf8. I honestly don't remember if it was mosh or my terminal, though. It seemed to happen more often when I used mosh, but I could be misremembering.
A few other issues I do remember running into (probably 10 years ago?):
1. Because it was udp, sometimes a captive portal, work, or hotel firewall blocked it.
2. It was also not installed by default anywhere, so sometimes sysadmins at work were unwilling to install it for me.
3. I sometimes ran into issues with color handling and utf8. I honestly don't remember if it was mosh or my terminal, though. It seemed to happen more often when I used mosh, but I could be misremembering.